Plug and receptacle construction



April 11, 1950 c. MILLER PLUG AND RECEPTACLE CONSTRUCTION 2 Sheets-Sheet 1 Filed June 22., 1948 M m m w.

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April 11, 1950 'c. MILLER 2,503,236

PLUG AND RECEPTACLE CONSTRUCTION Filed June 22, 1948- I =2 Sheets-Sheet 2 57 iixlL INVENTOR 09 5/5774 M115?- ATTORNEYS Patented Apr. 11, 1950 PLUG AND RECEPTACLE CONSTRUCTION Christian Miller, Norwalk, Conn., assignor to Edwards and Company, Inc., Norwalk, Conn., a corporation of New York Application June'22, 1948, Serial No. 34,535

' 10 Claims.

This application is a continuation in part of application Serial No. 742,694, now abandoned, filed April 19, 1947.

This invention relates to a disconnectable plug and receptacle construction for use in a hospital signalling system wherein the patient can actuate one or more signals and the circuits op erating those signals can be restored by the attendant only at the place the signal was initiated.

It is an object of the present invention to provide sucha plug and receptacle so designed that if the plug becomes detached from the receptacle the signal circuits are closed and the signals are actuated and remain so until re-set by an attendant.

It is a further object of the invention to provide such a device which can be set so that, despite the normal operation of the device, the signals will not be actuated after the plug is intentionally removed from the device.

It is still a further object of the invention to provide such a device in which, when it has been set so that the signals will not be actuated after removal of the plug, means are provided in the plug to put the device in operating condition upon insertion of the plug into the receptacle.

Further and additional objects will be in part obvious or in part pointed out hereinafter.

f The invention consists in the features of construction, combination of elements, and arrangement of parts as will-be exemplified in the construction hereinafter described and the scope of the application of which will be indicated in the followin claims.

In the accompanying drawings which form a part of this specification:

Fig. l is a plan view of the receptacle shown in a wall mounting plate;

Fig. 2 is an exploded view partly in cross section showing the plug and its contact fingers;

Fig. 3 is an exploded View partly in cross section of the receptacle;

Fig. 4 is a cross section of the receptacle on the line 4+4 of Fig. 1;

Fig. 5 is a fragmentary cross sectional view showing the special design of the receptacle contact finger connected to the ground or return circuit; I

Fig. 6 is a view in perspective of the operatingplunger;

Fig. 7 is a cross section on the line 'i--'! of Fig. 4 looking ill-the direction of the arrows adlacent those reference characters;

.Fig. 8 is a cross section on the line 8-8 of SEE 4 1951 Fig. 4 looking in the adjacent those characters;

Fig. 4;

Fig. 10 is a plan view of the conductive or short circuit plate;

Fig. 11 is a fragmentary cross section of the plug and receptacle in assembled position;

Fig. 12 is a fragmentary cross section showing the plunger'in its pre-set position to prevent actuation of the signals and the relative position of the co-operating plug elements.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Referring to Fig. l a wall mounting plate 20 is provided with appropriate openings so thatthe upper portion 2| of one or more receptaclesmay be secured therein fiush with outer face of mounting plate 20. Eachon-e of portions 2| accommodates a plug 22 to which electrical conductors 23 eXtending-to-the patients switching device (not shown) are attached.

Referring more particularly to Fig. 2 the plug consists of a casing 24-, mounting block 25 made completely assembled. Contact fingers 26 made I of electrically conductive material are providedwith spring V-bends 28. Theends of-electri cal conductors 23-are connected to the ends of contact fingers 26 at 21 and pass through holes" 29 in casing 24p Mounting block 25 is provided with an indentation 3li'having an inclined face 3|, the purpose of ,Whichwill be hereinafter scribed.

Referring to Figs. 3 and 4 the receptacle comprises two portions, upper portion 2! and lower portion 33 (as viewed'in Fig. 4), both are made of insulating material.- "Upper portion 2| is pro-" vided with lugs 34 whichi-fitinto recesses 36 inlower portion 33 (see Fig. 8). In order to insure that portions 2! and 33 are properly assembled, lugs Stand recesses 36- are of different size. Means are also provided, such as threaded holes 31 and-38 through which bolts maybe passed, to secure portionsZl and'33 firmly together afterassem'bly. 4

Theremay 'be-asmany signalling circuits as desired. In the form illustrated five contact fingers 26 areprovided for fourzsignalling circuits,

direction of the arrows.

Fig. 9 is a cross section on the line 99 of one contact finger functioning, as hereinafter described, to close the return or ground circuit. The circuits through the device are made from the patients switch (not shown) at the end of conductors 23, through contact fingers 26 in plug 22 to contact fingers 39 in receptacle 33 then to a permanent circuit in the wall through connectors 40. When the patient operates one or more switching devices the return circuit and one 01' more of the signalling circuits are closed in this manner. When the patient does not actuate the switching device these circuits are open at that device.

Contact fingers 39 (Figs. 3 and 4) are mounted in lower portion 33 ingrooves 4| designed for that purpose. Contact fingers 39 which are made of a resilient electrically conductive material are firmly held in place by screws 42 or in any other appropriate manner. However, for positive operation of the device there is mounted radially outside of contact fingers 39 one or more backing springs 43. Contact fingers 39 have spring V-bends 44, which when the device is assembled, co-operate with spring V-bends 28 in contact fingers 26 to move contact fingers 39 radially outward and to insure good electrical contact between the corresponding contact fingers 26 and 39. Contact fingers 39 are also provided with substantially U-shaped cam bends 45, the purpose of which will be hereinafter described.

It is obvious that when plug 22 is inserted in receptacle 2| and 33 contact fingers 26 pass through the holes 46 provided for that'purpose in portion 2| and engage contact fingers 39 as shown in Fig. 11. However,when plug 22 is detached from the receptacle it is obvious that the circuits are no longer completed through contact fingers 28 and 39 because these sets of fingers are separated.

This invention provides a means whereby signals can be transmitted when the above condition pertains. In general, this means comprises a conductive or short circuiting plate 41 positioned in a properly formed recess in the upper part of portion 33. Connection through plate 41 is made in the following manner: When plug 22 is detached, contact fingers 39 due to their shape and spring-like action move inwardly and contact plate 47, thus the circuits are completed from the permanent circuits in the wall through connectors 40, contact fingers 39, plate 41 and back through whichever contact finger 39 has been chosen for the ground or return circuit. In the case of the contact finger 39b chosen for the ground or return circuit a slightly different construction is employed as shown in Fig. 5. In the case of the return circuit there is no need to break the contact in the receptacle since all circuits are broken on the other side. Therefore, there is provided two contact fingers 39a. and 39b for this purpose. Contact finger 39a is arranged radially inside of contact finger 39b and in general is of the same shape but is shorter than contact finger 39?). Contact finger 39a is in contact with plate 41 at all times.

Frequently it is desired to remove plug 22 without actuating all or any of the signal circuits. This is accomplished in the present device by having a manually operated plunger 48 centrally disposed in an opening designed for that purpose in lower portion 33'. Plunger 48, as shown most clearly in Fig. 6, has an upper reduced or stem section 49 which, in its normal position as shown in Fig. 11, extends above the upper portion 2| into a recess 49a provided for that purpose in plug 22,

4 Below stem section 49, plunger 48 has a section 50 of enlarged diameter and having a laterally extending rectangular lug 58a extending over the length of section 50. Below section 50 is a frustoconical section 5| which has a fiat portion 5|a and below that is a stem section 52 of reduced diameter and of substantially the same diameter as stem section 49. As may be seen from Fig. 4 plunger 48 is disposed in receptacle portions 2| and 33 in the following manner when in its normal position: Sections 50 and 50a generally extend from upper portion 2| to and slightly into lower portion 33, the frusto-conical section 5| is located in lower portion 33' and the upper face of frustoconical section 5| is close to the lower surface of plate 47. The lower stem portion 52 extends through a central bore in lower section 33 almost to the bottom thereof. The bore through which stem section 52 extends is enlarged as shown at 53 to provide space for a spring surrounding stem section 52 and exerting pressure against the lower face of frusto-conical section 5|. In the position shown in Fig. 4 the part of frusto-conical section 5| which is of smaller diameter is opposite the U-shaped bends in contact fingers 39, thereby allowing contact fingers 39 to be in contact with plate 41 when plug 22 is withdrawn. If it is desired to prevent the signals being actuated when plug 22 is withdrawn, plunger 48 is depressed by an attendant as shown at 55 in Fig. 4. A washer GO is provided in portion 33 to prevent section of plunger 48 from striking the top of portion 35!.

This puts plunger 48 in the position shown in Fig. 12 and the portion of frusto-conical section 5| of larger diameter bears against the U-shaped bends 45 in contact fingers 39 moving them outwardly so that contact between contact fingers 39 and plate 41 is broken and the circuits are opened at that point. Neither contact finger 39a nor contact finger 39b for the return circuit is bent outwardly away from plate 41 by plunger 48 because plunger 48 is placed in the receptacle 7 portion 33 so that flat portion 5|a of frustoconical section 5| is adjacent to contact fingers 39a, 39b and does not result in any camming action. In order to keep plunger 48 in the position shown in Fig. 12 without having to continue pressure of the attendants finger a locking device is provided. This consists of ears 56 mounted on a spring device 51 and 51a attached to lower portion 33 in the manner shown at 58 or in any other suitable manner. signed that it tends to move ears 56 radially inward. In the normal position of plunger 48 these ears rest against the side of rectangular lug section 50a. However, when plunger 48 is depressed,

as in Fig. 12, ears 56 rest on the top surface of rectangular lug section 59a, thereby holding it down against the pressure of spring 54 and any vertical force exerted against frusto-conical section 5|. End 59 of spring 51 is shaped to cooperate with recess 38 and inclined wall 3| of that recess in plug 22 so that, as diagrammatically illustrated in Fig. 12, when plug 22 is inserted into the receptacle, surface 3| bears against spring end 59 so as to move it radially outward and release plunger 48. In this way plunger 48 returns to its normal position when plug 22 is inserted but contact between contact fingers 39 and plate 41 is prevented because contact fingers 25 have moved into position and forced contact fingers 1' to assure contact with contact fingers 39 but do Spring 51, 51a is so denotextend so that any of them can, at any time, touch plate 41.

I claim:

-1. In a hospital signalling system a plug and receptacle combination in which the plug has a plurality of electrical contacts and the receptacle has a plurality of corresponding spring-like electrical contacts, means comprising an electrically conductive plate adapted for contacting said contactsin said receptacle and thereby short circuitingthe circuits connected to said contacts when said plug is removed from said receptacle and means for manually preventing said contacts from contacting said plate, said last mentioned means including a manually operated plunger having a frusto conical section co-operating with said contacts in said receptacle.

2. In a hospital signalling system a plug and receptacle combination in which the plug has a plurality of electrical contacts and the receptacle has a plurality of corresponding spring-like electrical contacts, means comprising an electrically conductive plate adapted for contacting said contacts in said receptacle and'thereby short circuiting the circuits connected to said contacts when said plug is removed from said receptacle and means for manually preventing said contacts from contacting said plate, said last mentioned means including a manually operated plunger having a frusto-conical section co-operating with said contacts in said receptacle, and means for locking said plunger in a position where it prevents said contacts from contacting said plate.

3. In a hospital signalling system a plug and receptacle combination in which the plug has a plurality of electrical contacts and the receptacle has a plurality of corresponding spring-like electrical contacts, means comprising an electrically conductive plate adapted for contacting said contacts in said receptacle and thereby short circuiting the circuits connected to said contacts when said plug is removed from said receptacle and means for manually preventing said contacts from contacting said plate, said last mentioned means including a manually operated plunger having a frusto-conical section co-operating with said contacts in said receptacle, spring operated means for locking said plunger in position to prevent said contacts from contacting said plate and means contained in said plug for releasing said locking means when said plug is inserted in said receptacle.

4. In a hospital signalling system a plug and receptacle combination in which the plug has a plurality of electrical contacts and the receptacle has a plurality of corresponding spring-like electrical contacts, means comprising an electrically conductive plate adapted for contacting said contacts in said receptacle and thereby short circuiting the circuits connected to said contacts when said plug is removed from said receptacle and means for manually preventing said contacts from contacting said plate, said last mentioned means including a manually operated plunger having a frusto-conical section co-operating with said con tacts in said receptacle, spring operated means for locking said plunger in position to prevent said contacts from contacting said plate and means contained in said plug for releasing said locking means when said plug is inserted in said receptacle, said releasing means comprising a camacting surface in said plug co-operating with an extension of said spring operated means.

5. A signalling plug and receptacle construction comprising a plug body having a plurality of plug contacts projecting'from its bottom end,

sulating material projfectable out of said end face and said plug body having a hollow space in itsbottom end into which a portion of said moveablemember may enter, means including sald plug contacts responsive to disengagement of said plug from said receptacle for effecting closure or at least certain of said signalling circuits and" means including said frusto-conical section re- .sponsive to inward movement of said moveable all) member from its projected position for eil'ecting opening of the signalling circuits that are closed in response to disengagement of the plug contacts from the receptacle, a moveable control member carried by said receptacle body and accessible through its said end faceandhaving means operating to hold said spring-biased member in inward position against the bias of its spring and operable in response to movement of said control member to release said spring-biased member for outward projection, and means exposed at the bottom end of said plug body and movable relative to said plug body for engagement with said moveable control member to effect movement thereon in a direction to release said moveable spring-biased member.

6. A signalling plug and receptacle construction as claimed in claim 5 in which said last mentioned means comprises a cam element at the bottom end of the plug body, said cam element having a cam face that is inclined to the direction of movement of assembly of the plug body to the receptacle body to thereby efiect movement of said moveable control element upon assembly of the plug body and its plug contacts to the receptacle body and its contact elements respectively.

7. A signalling plug and receptacle construction as claimed in claim 5 in which said last mentioned means comprises an operating element having means mounting it for movement relative to the plug body and along a path to engage said moveable control member and effecting movement thereof, and means operable from the exterior of said plug body for effecting movement of said moveable element.

8. A signalling plug and receptacle construction as claimed in claim 5 in which said last mentioned means comprises an operating element having means mounting it for movement relative to the plug body and along a path to engage said moveable control member and effecting movement thereof, said receptacle body having extending therefrom a spring-retracted tension element, and means responsive to a stroke of movement of said tension element for operating said moveable element to actuate said springbiased control member.

9. A signalling plug and receptacle construction as claimed in claim 5 in which said springbiased projectable member of the receptacle body and the hollow space in the bottom end of the plug body are positioned substantially at the axis; said means at-the bottom end of the plug body for eifecting movement of said control member; comprising cam means engageable with said control member upon movement of assembly of the-plug body to the receptacle body and having a: cam face to'resolve the force of said movement of assembly into a radial component to effect movement of said control-member.

10. A'signalling plug and receptacle construction comprising a plug body having plug contactsand' a receptacle body having a plurality of'recesses forthe reception of plug contacts into the 'receptacle'recesses, a plurality of spring con tacts carried by said receptacle body and respectively exposed in such recesses for engagement respectively by such plug contacts as are entered thereinto, said spring contacts being biased inwardly and said receptacle body having therein conductive means with which said inwardly biased contact springs engage, whereby, upon disassembly of said plug body from said receptacle body, said spring contacts move inwardly and engage said conductive means, spring opposed movable means within said receptacle body REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,911,513 Kenerson May 30, 1933 2,239,035 Curtiss Apr. 22, 1941 2.405,735 Crockett Aug. 13, 1946 

